Trailer coupling of the ball and socket type



Feb. 18, 1958 c. SCHRADER TRAILER COUPLING OF THE BALL AND SOCKET TYPEFiled Nov. 7, 1955 3 Sheets-Sheet 1 INVENTOR.

LEROY C SCHRADER ATTORNEYS Feb. 18, 1958 L. c. SCHRADER 2,823,931

TRAILER COUPLING OF THE BALL AND SOCKET TYPE Filed Nov. 7, 1955 3Sheets-Sheet 2 INVENTOR. LEROY C. SCHRADER yM #LMYmm /K ATTORNEYS Feb.18, 1958 L. c. SCHRADER TRAILER COUPLING OF THE BALL AND SOCKET TYPE 3Sheets-Sheet 3 Filed NOV. 7, 1955 fill/III!!! INVENTOR. LEROY C.SCHRADER ATTORN EYS United States Patent TRAILER COUPLING OF THE BALLAND SOCKET TYPE Le Roy C. Schrader, Sturgis, Mich., assignor to MarvelIndustries, Inc., Sturgis, MiclL, a corporation of Michigan ApplicationNovember 7, 1955, Serial No. 545,158

3 Claims. (Cl. 280-513) The invention relates to trailer couplings ofthat type in which the tongue or draft member of the vehicle isconnected to the draft vehicle by a ball and socket coupling, togetherwith mechanism by which said members may be locked against disengagementfrom each other and released when so desired. It is the object of theinvention to simplify this locking mechanism and also to reduce thedimensions of the structure in which it is installed. To this end theinvention consists in the construction as hereinafter set forth.

In the accompanying drawings:

Fig. l is a plan view of the trailer coupling.

Fig. 2 is a longitudinal section on line 22, Fig. 1.

Fig. 3 is a side elevation of the locking member detached.

Fig. 4 is a front elevation thereof.

Fig. 5 is a cross section on line 5-5, Fig. 4.

Fig. 6 is an elevation of the operating lever detached.

Fig. 7 is a bottom plan view thereof.

Fig. 8 is a cross section on line 8-8, Fig. 6.

Fig. 9 is a cross section on line 99, Fig. 6.

Figs. 10, 11 and 12 are sections respectively on lines 10-10, 1111 and12-12, Fig. 2.

As heretofore constructed couplers of this type have usually included asegmental spherical socket member which is less than a semisphere inextent and a supplemental segmental member pivotally attached to theformer to swing between a locking and a releasing position. In theformer it extends the spherical socket to more than a semisphere whilein the latter position it opens the socket to the full diameter of theball so as to permit engagement or disengagement thereof. The mechanismfor manually operating and controlling this pivotal member usuallyincludes a number of separate elements, such as cams, rock shafts, etc.I have simplified the construction reducing the number of separateelements and reorganizing those that are retained.

As illustrated in Figs. 1 and 2, A is a casting for attachment to thetongue of the trailer and which is provided with diverging rearwardlyextending angle portions A and A for attachment to the converging draftbars of the tongue. Forward of the point of divergence the member A hasa portion A of inverted U-shaped cross section which at its top isapertured at A for the passage of a vertically adjustable post (notshown) used for engaging and disengaging the ball and socket members andalso supporting the tongue of the trailer when detached from the trailervehicle. Forward of the portion A the casting is reduced in width at Aand is provided therein with a cross wall A having an arcuate portion Atherein. Forward of the portion A the casting is expanded in width toform a segmental spherical socket portion A which is less than asemisphere in extent and is in advance and above an oblique plane. Thecenter of this semisphere is below the center of the arcuate portion Aand is also spaced from the latter by a dimension greater than theradius of said semisphere. Both of these portions extend below thehorizontal plane of the center of the semisphere so that the portion Abelow the plane of its center converges towards the portion A. Above theportion A is a still narrower portion A which extends upward to thelevel of the top of the portion A With the construction as abovedescribed the opening from the bottom into the segmental sphericalsocket A is equal in Width to the diameter of said socket and hasoutwardly flaring flanges A at the lower end thereof for guiding theball member (not shown) into the socket. Longitudinally the opening inrear of the portion A is at least equal or greater than the diameter ofthe socket so that to in no way interfere with the entrance of the ball.

B is the locking member for the ball within the socket A which is freefrom the member A and has on its forward face a segmental sphericalportion B complementary to the portion A and at its rear has spacedportions B B which are arcuate and of a radius equal to that of thearcuate portion A". The centers of the portions B and B B are in thesame relation to each other as the corresponding portions in the memberA which gives to the member B a downwardly tapering wedge shaped form. Cis a rod pivotally attached at its lower end to the upper end of themember B by a pin C This rod extends obliquely upward through theportion A and outward through an aperture in the top A of this portionwhich is inclined substantially at right angles to the inclination ofthe rod. The outer end of the rod is pivotally connected by a pin C witha lever D. There is also a coil spring E sleeved on the rod C extendingbetween the portion A and the upper end of the member B, beingprecompressed to resiliently force said member B downward. The lever Dmay be formed of pressed sheet metal of U-shaped cross section toembrace the upper end portion of the rod C and extends oppositely fromthe pin C The sides D of the U-shaped section in the portion thereofextending to the left, Fig. 2, have their edges fashioned to form a camwhich when the lever is turned on the pin C will bear against theportion A and draw the rod C outward against the tension of the springE. When this portion of the lever is in substantial alignment with therod the end D bearing on the portion A will hold the parts in thisposition. Such outward movement of the rod C will draw the member Bupward around the arcuate bearing A", thereby opening the socket forentrance or disengagement of the ball member. The portion D of the leverD extending to the right of the pin C Fig. 2, forms an operating handle.The side flanges of this portion are apertured to embrace a similarlyapertured lug F extending upward from the member A to which it issecured. As shown this lug F is formed integral with a plate F whichextends along the top of the member A and is bolted or otherwise securedthereto. This plate is apertured and provided with an annular flange Fsurrounding the same for engagement with the lifting post (not shown).

In operation to effect the coupling between the ball and socket, thelever D is turned into a position where it withdraws the member B topermit free entry of the ball. The lever is then turned into theposition shown in Fig. 2, the spring E forcing the rod C downward andmoving the wedge shaped member B around the arcuate curve A". As thiscurve converges towards the circle of the socket the member B when moveddownward will also move laterally towards this circle until thesegmental spherical surface B coincides therewith. In this position thesocket portion A supplemented by the portion B extends more than asemisphere and will therefore hold the ball from disengagement. Allportions of the curve A will be within the angle of friction withrespect to draft stresses in the ball so that the latter cannot displacethe member 13. However, at any time operation of the lever D willwithdraw the member B to permit disengagement of the coupling. In thenormal position of the lever D, shown in Fig. 2, the cam D is spacedfrom the portion A of the casting. Thus, any wear in the member B whichreduces its widthwill be compensated for by a further tion limited inextent to not more than one-half of the sphere butextending below aswell as abovethe horizontal plane of its center, a separatelongitudinally movable member of tapering wedge form, one side of whichand in one position thereof forms an extension of said socket to morethan one-half the sphere, the other side being an eccentric arcuatecurve, and a wall portion of said draft member in rear of and rigid withsaid socket portion having a similar arcuate curved surface in contactwith that of said wedge and within the angle of friction relative todisplacement of said movable member by any draft stresses transmittedthrough said coupling and operating means'for withdrawing said wedgelongitudinally along said arcuate wall surface until the opening intosaid socket is equal to its internal diameter.

2. The construction as in claim 1 in which said operating means consistsof a rod pivotally attached to said movable wedge member and extendingupward through an aperture in the top of said draft member to above thesame, a lever fulcrumed on said draft member pivotally connected to theupper end of said rod and a spring sleeved on said rod between the topof said draft member and said wedge for forcing the latter downward.

3. The construction as in claim 1 in which the arcuate surface of saidwall extends below the horizontal plane of its center.

References Cited in the file of this patent UNITED STATES PATENTS2,115,629 Gurley Apr. 26, 1938 2,149,189 Shaffer Feb. 28, 19392,166,208.: Dayton July 18, 1939 Berluti Oct. 31, 1939

